Optical chip-scale package for use in a high channel density, high data rate data communications system having optical input/output (I/O) ports

Abstract

An optical chip-scale package (CSP) is provided for use in a high channel density, high data rate communications system that has optical I/O ports and that is capable of being housed in a standard rackmount-sized box. The optical I/O ports comprise a bulkhead of multi-optical fiber (MF) adapters installed in a front panel of a switch box that houses the communications system. The adapters have first and second receptacles that are adapted to mate with first and second MF connectors, respectively. The communications system comprises a single-harness optical subassembly that uses a plurality of the optical CSPs that interface with a switch IC chip of the communications system to perform electrical-to-optical and optical-to-electrical conversion.

What is claimed is: 
     
       1. An optical chip-scale package (CSP) comprising:
 an interposer having a top surface and a bottom surface, the top and bottom surfaces of the interposer having a first and a second electrical interface thereon, respectively, the first and second electrical interfaces comprising a first plurality and a second plurality of electrical contacts, respectively, the interposer having electrical conductors and electrical vias therein; 
 at least a first array of lenses disposed on the interposer, the first array of lenses having N lenses, where N is a positive integer that is greater than or equal to one; 
 an integrated circuit (IC) die having a first side and a second side, the first side of the IC die having a plurality of electrical contacts thereon, the IC die being flip-chip mounted on the bottom surface of the interposer such that electrical contacts of the IC die are in contact with respective electrical contacts of said second plurality of electrical contacts; and 
 at least a first optoelectronic die mounted on the interposer, the first optoelectronic die having a plurality of electrical contacts thereon and having at least N optoelectronic devices integrated therein having N apertures, respectively, and wherein electrical contacts of said at least a first optoelectronic die are electrically coupled with respective electrical contacts of one of the first and second pluralities of electrical contacts, and wherein electrical contacts of said at least a first optoelectronic die are electrically coupled via the electrical conductors of the interposer with electrical contacts of the plurality of electrical contacts disposed on the first side of the IC die. 
 
     
     
       2. The optical CSP of  claim 1 , wherein the first optoelectronic die is flip-chip mounted on the bottom surface of the interposer such that the electrical contacts of said at least a first optoelectronic die are in contact with respective electrical contacts of the second plurality of electrical contacts disposed on the bottom surface of the interposer, and wherein the N lenses are optically aligned with the N apertures. 
     
     
       3. The optical CSP of  claim 1 , wherein said at least a first optoelectronic die comprises a plurality of optoelectronic dies that are flip-chip mounted on the bottom surface of the interposer such that electrical contacts of the optoelectronic dies are in contact with respective electrical contacts of the second plurality of electrical contacts disposed on the bottom surface of the interposer, each optoelectronic die comprising a plurality of optoelectronic devices, and wherein the N lenses are optically aligned with the N apertures of the optoelectronic devices. 
     
     
       4. The optical CSP of  claim 1 , wherein said at least a first optoelectronic die comprises N optoelectronic dies that are flip-chip mounted on the bottom surface of the interposer such that electrical contacts of the optoelectronic dies are in contact with respective electrical contacts of the second plurality of electrical contacts disposed on the bottom surface of the interposer, each optoelectronic die comprising a single optoelectronic device, and wherein the N lenses are optically aligned with the N apertures of the N optoelectronic devices. 
     
     
       5. The optical CSP of  claim 1 , wherein the interposer is transparent to an operating wavelength of said at least N optoelectronic devices, wherein the first array of lenses is formed in or disposed on the top surface of the interposer, and wherein the optical CSP further comprises:
 a second array of lenses formed in or disposed on the interposer, the second array of lenses comprising N lenses, each lens of the second array of lenses being positioned in between a respective aperture and a lens of the first array of lenses. 
 
     
     
       6. The optical CSP of  claim 1 , wherein the interposer comprises a thermally-insulating material having a thermal conductivity that is less than or equal to 3 watts per meter-kelvin. 
     
     
       7. The optical CSP of  claim 1 , further comprising:
 at least a first passive alignment device disposed on the top surface of the interposer for passively aligning an external optics system with the first array of lenses, wherein when the external optics system is passively aligned with the first array of lenses, each of the N lenses is optically aligned with a respective optical pathway of the external optics system for coupling respective optical signals between the lenses of the first array of lenses and the respective optical pathways of the external optics system. 
 
     
     
       8. The optical CSP of  claim 1 , further comprising:
 a lid made of a highly thermally conductive (HTC) material, the lid having a front surface and a back surface, the front surface of the lid being mechanically and thermally coupled to the IC die and to said at least a first optoelectronic die. 
 
     
     
       9. The optical CSP of  claim 8 , wherein the HTC material has a thermal conductivity that is greater than or equal to 50 watts per meter-kelvin. 
     
     
       10. The optical CSP of  claim 8 , further comprising:
 a frame that mechanically couples the front surface of the lid to the bottom surface of the interposer, the frame having a first side that is mechanically coupled to the bottom surface of the interposer and having a second side that is mechanically coupled to the front surface of the lid, and wherein the frame spaces the front surface of the lid a predetermined distance away from the bottom surface of the interposer to provide space for at least the first IC die. 
 
     
     
       11. The optical CSP of  claim 8 , further comprising:
 a layer of thermally-conductive material is disposed in between and in contact with the front surface of the lid and the second side of the IC die. 
 
     
     
       12. The optical CSP of  claim 11 , wherein said N apertures are located in a front side of said at least a first optoelectronic die, and wherein the layer of thermally-conductive material is also in contact with a back side of said at least a first optoelectronic die opposite the front side of said at least a first optoelectronic die. 
     
     
       13. An optical chip-scale package (CSP) comprising:
 an interposer having a top surface and a bottom surface, the top and bottom surfaces of the interposer having a first and a second electrical interface thereon, respectively, the first and second electrical interfaces comprising a first plurality and a second plurality of electrical contacts, respectively, the interposer having electrical conductors and electrical vias therein and being transparent to an operating wavelength of light; 
 at least a first array of lenses disposed on the top surface of the interposer on a portion of the interposer that does not include the first and second electrical interfaces and that is configured to extend a distance beyond a periphery of a substrate on which the optical CSP will be mounted, the first array of lenses having N lenses, where N is a positive integer that is greater than or equal to two; 
 an integrated circuit (IC) die having a first side and a second side, the first side of the IC die having a plurality of electrical contacts thereon, the IC die being flip-chip mounted on the bottom surface of the interposer such that the electrical contacts of the IC die are in contact with respective electrical contacts of the second plurality of electrical contacts; and 
 at least a first optoelectronic die flip-chip mounted on the bottom surface of the interposer such that a plurality of electrical contacts of said at least a first optoelectronic die are in contact with respective electrical contacts of the second plurality of electrical contacts disposed on the bottom surface of the interposer, the first optoelectronic die having at least N optoelectronic devices integrated therein having N apertures, respectively, said operating wavelength of light being an operating wavelength of light of the N optoelectronic devices, and wherein the N lenses are optically aligned with the N apertures, and wherein electrical contacts of said plurality of electrical contacts of said at least a first optoelectronic die are electrically coupled by the electrical conductors or vias of the interposer with electrical contacts of the plurality of electrical contacts disposed on the first side of the IC die. 
 
     
     
       14. The optical CSP of  claim 13 , further comprising:
 a second array of lenses disposed on the interposer, the second array of lenses comprising N lenses, each lens of the second array of lenses being positioned in between a respective aperture of the N apertures and a lens of the first array of lenses. 
 
     
     
       15. The optical CSP of  claim 13 , wherein the interposer comprises a thermally-insulating material. 
     
     
       16. The optical CSP of  claim 13 , further comprising:
 at least a first passive alignment device disposed on the top surface of the interposer for engaging at least a first passive alignment device of an external optics system via an interference fit to passively aligning the external optics system with the first array of lenses, wherein when the external optics system is passively aligned with the first array of lenses, each of the N lenses is optically aligned with a respective optical pathways of the external optics system for coupling respective optical signals between the lenses of the first array of lenses and the respective optical pathways of the external optics system. 
 
     
     
       17. The optical CSP of  claim 13 , further comprising:
 a lid made of a highly thermally conductive (HTC) material, the lid having a front surface and a back surface, the front surface of the lid being mechanically and thermally coupled to the IC die and to said at least a first optoelectronic die. 
 
     
     
       18. The optical CSP of  claim 17 , further comprising:
 a frame that mechanically couples the front surface of the lid to the bottom surface of the interposer, the frame having a first side that is mechanically coupled to the bottom surface of the interposer and having a second side that is mechanically coupled to the front surface of the lid, and wherein the frame spaces the front surface of the lid a predetermined distance away from the bottom surface of the interposer to provide space for at least the first IC die. 
 
     
     
       19. The optical CSP of  claim 17 , further comprising:
 a layer of thermally-conductive material disposed in between and in contact with the front surface of the lid and the second side of the IC chip. 
 
     
     
       20. A single-harness optical subassembly configured for use with the optical CSP of  claim 13 , comprising:
 a central portion having an opening therein; 
 a plurality of optics systems disposed along a periphery of the opening, each optics system being adapted to mechanically and optically couple with the interposer of a respective optical CSP along the portion of the interposer on which the first array of lenses is disposed; 
 a first optical fiber holder having a first end that is mechanically coupled with a first side of the central portion, the first optical fiber holder having a second end that is mechanically coupled with a first bulkhead adapter; 
 a second optical fiber holder having a first end that is mechanically coupled with a second side of the central portion, the second optical fiber holder having a second end that is mechanically coupled with a second bulkhead adapter; 
 a first plurality of optical fibers extending from a first plurality of the optics systems over the first optical fiber holder to the first bulkhead adapter; and 
 a second plurality of optical fibers extending from a second plurality of the optics systems over the second optical fiber holder to the second bulkhead adapter. 
 
     
     
       21. The single-harness optical subassembly of  claim 20 , wherein the first and second bulkhead adapters each comprise first and second pluralities of adapters, each adapter having a first receptacle configured to mate with a first multi-optical fiber (MF) connector that is configured to hold ends of a plurality of optical fibers.